I use Dice. It's a fairly simple install. Major benefits are you can control the iPod from radio and steer wheel controls with text display and it'll keep your iPod/iPhone charged while plugged in. You'll also gain a seperate Aux port as well. Downside is (at least for me) there's faint noise or interference in the background that can only be heard when the music is soft. I've been too lazy to recheck my lines to see if it's touching something that it's not suppose to.
I got mine off eBay for $90 bucks.